Trichromatic-process transparency.



:F. E. I vBs. TRIGHROMATIG PROCESS TRANSPARENCY.

APPLICATION FILED SEPT. 3, 1902.

N0. 725,566. PATENTED APR, 14, 1903.,

No MODEL.-

NITED STA E PATENT OFFICE.

FREDERIO E. IVES, OF PHILADELPHIA, PENNSYLVANIA.

TRlCHROlVlATlC-PROCESS TRANSPARENCY.

SPECIFICATION formingpart of Letters Patent No. 725,566, dated April 14, 1903.

Application filed September 3, 1902. Serial lib-121,973. (No model.)

To all whom it may concern.-

Be it known that I, FREDERIC E. Ivns, a citizen of the United States, residing in Philadelphia,Pennsylvania,have invented certain Improvements in Trichromatic-Process Transparencies, of which the following is a specification.

My invention relates to the production of colored transparencies,such as lantern-slides,

by the so-called trichromatic photographicprocess, and is designed to cheapen and render more reliable the commercial production of such pictures.

In the accompanying drawings, Figures 1, 2, and 3 illustrate three colored transparencies made in accordance with iny invention.

The basis for such'colored transparencies is a set of three negativeimages, which should be made in accordance with my patent otJuly 22, 1890, No. 432,530. Such negatives are most readily and reliably produced in one of the cameras described in my Patents No. 475,084, May 17, 1892; No. 546,889, September 24, 1895; No. 632,573, September 5, 1899; No. 655,712, August 14, 1900; No. 660,442, October 23, 1900; No. 668,989, February 26, 1901;No.703,929,Ju1y 1,1902; and N0.707,421, August 19, 1902. p

The most perfect method which has so far been devised for making the colored transparencies consists, first, in printing from the three negatives three positives in bichromated gelatin attached to a clear celluloid film, (exposing through the cel1uloid,) then washing away from the other side by means of warm water the parts not fixed by light; second, in immersing the separate gelatin prints in aqueous solutions of suitable dyes until they attain a suitable depth of color, and, third, in drying these colored prints and then superposing them between glasses to form the single composite-color picture. This process iscapable of producing very perfect results; but it is not sufficiently simple or sufficiently reliable in the hands of average skilled workmen to afford a means of making such pictures at pricesto compete with handcolored photographic transparencies, except in special cases.

Perhaps the cheapest method that could be rious objection to this method is the line or I stipple structure of the half-tone process, which becomes offensive when magnified upon a screen, as in lantern projection. This pattern is, however, usually much more evident visually in the greenish-blue print, which is the one obtained" from the negative representing the red sensation, than in the crimson-pink and yellow prints, which are obtained, respectively, from the negatives representing the green and blue sensations, because the latter are less critical as to definition and gradation of light and shade in the finished result, and I therefore propose as a means for eliminating the tediousness and uncertainty pertaining to the first-described process without introducing too much lining or granularity to combine a structureless blue-print with half-tone red and yellow prints, all of which canbe produced with comparative ease and certainty by wellknown methods. Iprefer to make the blueprint by converting an ordinary photographic transparency from the respective negative image by treatment with ferricyanid of potassium and perchlorid of iron, a well-known process. From the other two negative images half-tone typographic, lithographic, or intaglio printing-surfaces may be made by any of the well-known processes, and prints upon clear celluloid sheets made in suitable colored inks from these printing-surfaces may be superposed upon the structureless blue-print, thereby producing a compositecolor print having therequisite qualities for commercial exploitation. V

- In the drawings, a, b, and 0 represent the three transparent sheets, a, and-b the line or stipple images, and c the structureless or body-shaded image. The latter, however, is not a true representation of the body-shades of a photographically-printed image, as the limitations imposed upon the draft-sman by the rules governing the preparation of drawings will not permit of a correct representation of body-shading.

Some of the advantages of converting the crimson-red and yellow images into half-tone line or stipple may be realized Without going so far as to produce process-blocks and print them in the printing-press. For example, prints upon the surface of bichromated gelatin when made in definite line and stipple may be converted into color-prints by several procedures, which are all more simple and reliable than the production and staining up of the graduated relief'prints first described. They may be dampened and then inked up with a printers ink-roller, the ink adhering only on the lines and dots impressed by light through the negative, and the line or stipple ink picture thus obtained may either be used as it is or employed to impress an image upon another surface. If the bichromated gelatin is very thin, it may be developed by means of warm Water applied to its face, and the lines and dots in gelatin which remain can be colored up evenly with far greater facility and less risk of failure than the graduated relief-images; which are necessarily made much thicker in order to preserve the gradations.

What is meant by a structureless image is one having body-shades as distinguished from the interrupted shadings produced by line or stipple.

Having thus described my invention, I claim and desire to secure by Letters Patent- 1. A trichromatic-process transparency combining one image containing body-shades and two images in which the body-shades are translated into definite line or stipple, substantially as specified.

2. A trichromatic process transparency combining one photographically-printed image and two mechanically-printed images, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FREDERIG E. IVES.

Witnesses:

F. E. BEoHToLn, Jos. H. KLEIN. 

